"I firmly believe that state-sanctioned killing is incompatible with California's values, undermines the foundations of our legal system, and diminishes each of us," Newsom, a lame-duck Democrat, wrote in an open letter to the state.

The promise cannot be implemented without support from the California Supreme Court. The state constitution requires a recommendation from the high court before a governor can commute the sentence of anyone convicted of more than one felony, and at least four justices must concur. Newsom asked the justices to weigh in on 382 of the capital cases and requested a recommendation by the end of the year so he can act before his term ends.

Newsom is widely expected to seek the Democratic presidential nomination in 2028, though he has not declared his candidacy.

If the sentences are commuted, the affected prisoners would be excluded from new state parole board commutation and resentencing rules that might further reduce their time incarcerated, Newsom said.

In a statement to the court, his office argued that the governor's clemency power is "plenary" and can be granted without applications, citing past grants of group clemency by presidents and governors. The court's role, it said, is not to judge the merits of the commutation but to guard against abuse of power.

During his two terms, Newsom has taken other steps to limit capital punishment. He imposed a moratorium on executions in March 2019; absent that moratorium, 45 people would be immediately subject to execution, he said. In 2022, he ordered a remodel of San Quentin prison in Marin County that shut down the death-row wing. California's last execution took place in January 2006.

The governor rejected calls to spare only some inmates, saying he considered different categories of crimes and offenders. Distinguishing among them "would inadvertently create two classes of murder victims," he said.

Newsom acknowledged the decision will anger some Californians, including some victims' families. "As governor, I alone bear responsibility for this decision and its impact," he wrote. He noted that voters have kept capital punishment on the books and that only the Legislature and voters can repeal it.

The Criminal Justice Legal Foundation, which advocates for victims' rights, told the New York Times it plans to sue Newsom over the reductions.

His office said it is working with state services to notify victims, survivors and next of kin, and will coordinate with district attorneys and the attorney general.

"Governor Newsom's decision to change all death sentences to life without parole sentences marks a new era of justice in our State," Attorney General Rob Bonta said Thursday afternoon. "As California's top law enforcement official, I have expressed concern that the death penalty is immoral," Bonta added. "I also believe that we must never lose sight of the experiences of victims and survivors and the pain and trauma they have endured. I commend Governor Newsom for taking this action."

Danielle Harris, managing attorney of the San Francisco Public Defender's Freedom Project, which assists people serving excessive prison sentences who have become eligible for release, praised the decision. "We are beyond grateful to see the governor's values align with ours," Harris said in a statement.

She called the death penalty a system "replete with error and racism" that consumes resources that could go toward violence prevention, healing and community well-being. Harris said she was relieved for those personally affected, their families and communities, and for the prison and medical staff who would have had to take part in executions.

Asked about commuting every sentence at once rather than reviewing cases individually, Harris said she read the governor's statement to mean he did review them individually and found no humane basis to distinguish among them. "If the penalty itself is inhumane, no case can qualify for it," she said, adding that the governor has discretion to grant commutations under the state constitution.

She said the office has one former client on death row, whose situation "will not change practically at all," though she said his emotional state would improve, making him a better community member and creating a more positive environment for those around him.

The San Francisco district attorney's office did not respond to a request for comment.

Los Angeles County has sentenced 104 people to death since 2000, the most in the state, according to the Death Penalty Information Center. San Francisco has had no death penalty sentence since then, the DPIC said. In that timeframe, Alameda County juries sentenced 19 inmates to death, the most in the Bay Area. Across the state, five people were sentenced to death in 2025, according to the DPIC.

Newsom's 2019 moratorium on executions led to the transfer of 700 death-row inmates from San Quentin to other prisons as part of an initiative to improve living conditions. As of Wednesday, there were 2,211 occupants of San Quentin Rehabilitation Center, nearly 72% of its 3,084-person capacity, according to state records.